Various attempts have been made to provide the simple and convenient arrangement for removably attaching a hook to a load lift chain. Of these, the simplest form would appear to involve forming the hook with a clevis whose legs are spaced apart sufficiently to receive the end link of a load chain and are through bored to receive a load pin, which is sized to be slip-fitted through the last link and to be end supported within the bore openings.
In these prior constructions, the load pins have been normally formed with either a circular or an oval cross-sectional configuration; the latter design serving to maximize shear strength and resistance to bending. Prior constructions of this type are disclosed for instance by U.S. Pat. Nos. 1,393,568 and 1,562,908.